Technical Field
This application is directed to controlling a power converter, and in particular controlling an LLC converter having two independent outputs.
Description of the Related Art
Dual independent output LLC converters are a class of converters characterized in that they output two voltages that are independent of each other. The output voltages may be used to supply power to one or more devices. Because this class of converters provides two independent output voltages and the two output voltages are taken into account in performing the control, conventional control of the converters is computationally intensive. Some conventional solutions (such as that described in R. Elferich and T. Duerbaum, “A New Load Resonant Dual-Output Converter,” Proceedings of the 33rd Annual IEEE Power Electronics Specialists Conference, 2002) utilize multidimensional control which increases the computational complexity required from control devices to operate the converter.
Other solutions, such as Bang-Bang charge control (BBCC) described in Z, Hu, Y. Liu, and P. C. Sen, “Bang-Bang Charge Control for LLC Resonant Converters,” IEEE Transactions on Power Electronics, Vol. 30, No. 2, February 2015, simplify the control of dual-output LLC converters. However, such solutions simplify control at the expense of introducing critical conditions that can disrupt operation of the converter.
Accordingly, a method and a controller for controlling a dual independent output LLC converter are desired. In addition, it is also desirable for the method and controller to simplify control of the LLC converter while at the same time maintaining stability in the operation of the LLC converter.